I couldn't find any information on this online. Which of the following sequencing technologies are considered short read technologies? Illumina, Oxford Nanopore, Ion Torrent, Pacific Biosciences
As mentioned by Greg, list of short-read sequencing platforms is listed on wikipedia.
Of those you mentioned Illumina and Ion Torrent are short-read sequencing platforms.
Usually what makes short reads short is a PCR step in the library prep or directly on the flowcell to amplify the signal, which is the limitation for how long stretches of DNA are possible to sequence. Long read sequencing technologies sequence directly isolated single molecules.